Applying a gradient glow produces a glow look with a gradient color across the surface of the glow. The gradient glow requires one color at the beginning of the gradient with an Alpha value of 0. You cannot move the position of this color, but you can change the color.

Select the type of glow to apply to the object from the Glow Type pop‑up menu.
To set the width and height of the glow, drag the Blur X and Y slider.
To set the opacity of the glow without affecting its width, drag the Strength slider.
To change the angle of the shadow that the glow casts, drag the Angle dial or enter a value.
To set the distance of the shadow from the object, drag the Distance slider.
To knock out (or visually hide) the source object and display only the gradient glow on the knockout image, select Knockout.
Specify a gradient color for the glow. A gradient contains two or more colors that fade or blend into one another. The color you select for the beginning of the gradient is referred to as the alpha color.
To change a color in the gradient, select one of the color pointers below the gradient definition bar and click the color space that appears directly below the gradient bar to display the Color Picker. Sliding these pointers adjusts the level and position of that color in the gradient.
To add a pointer to the gradient, click on or below the gradient definition bar. To create a gradient with up to 15 color transitions, add up to 15 color pointers. To reposition a pointer on the gradient, drag the pointer along the gradient definition bar. To remove a pointer, drag it down and off the gradient definition bar.
Select the quality level for the gradient glow. High is approximate to that of a Gaussian blur. Low maximizes playback performance.